Summary It is widely held that energy creation and use strategies employed by tumors may provide important diagnostic and therapeutic opportunities. However, tools to directly and microscopically visualize these strategies do not yet exist because most of the metabolites cannot be labeled for microscopy. This project uses recently developed a coherent Raman imaging method that can rapidly obtain molecular vibration signatures of these unlabeled metabolites, potentially making them visible. If the project is successful, it will yeild a microscope that will allow cancer researchers and clinicians to, for the ?rst time, visualize metabolic activity in intact tumors, on a cell-by-cell basis, and should facilitate discovery of new therapies and diagnostics. Developing such an instrument presents signi?cant challenges. The project will approach these in our ?rst Aim by developing a detailed theoretical model of our imaging approach, and testing it against a simpli?ed and well-controlled series of experimental tissue mimics. This dual model approach will allow us to discover the most effective path to realizing the necessary instrument sensitivity and reliability. In the second Aim we test the microscope in actual tissues and cell culture that is independently analyzed for content of metabolites measure by BCARS.